1. Field of the Invention
This invention relates to traffic directors of the type adapted to present physical barriers to passage of vehicles in a particular direction.
2. Description of the Prior Art
It is known to employ one-way traffic barriers in which teeth are projected from a housing in which they are rotatably mounted, and to lower the teeth into the housing when it is desired that there be no barrier to traffic in either direction. Thus, in U.S. Pat. No. 1,563,367 issued Dec. 1, 1925 for "Railway Crossing Guard," a plurality of teeth are secured to a shaft that is supported below a surface plate in an embedded housing. The teeth are normally lowered and retained in slots in the surface plate via counterweight means. To raise the teeth so they project above the roadbed to act as a barrier to traffic, solenoids are mounted at the ends of the embedded housing, and armatures for the solenoids are curved arms fixed to the shaft. The solenoids are energized by pressure of a train against a section of track adapted to close the solenoid power circuit, during which time the teeth project so as to prevent traffic from passing over them towards the tracks. After the train clears the wired track section, the circuit is broken and the solenoids deenergized to permit the teeth to lower into the slots.
It is also known to provide one-way traffic barriers in which teeth are individually pivoted. In such apparatus as heretofore made and sold, each tooth is welded to a hub that is rotatable on a shaft that is mounted at its ends in the ends of the embedded housing. Each hub has a welded finger thereon that extends at an obtuse angle from the tooth, and a tension spring is connected at its ends to the finger and to a side wall of the embedded housing.
The first-mentioned type of barrier is not practicable for use as a perpetual barrier in view of the constant power requirements to keep solenoids energized and the teeth raised. Also, such a system imposes severe burdens on the circuitry and teeth since each vehicle passing over the teeth in one direction would force all the teeth down, thus forcibly withdrawing the cores of the solenoids from their coils, because the shaft is rotated to withdraw the cores. This action occurs twice for each vehicle, since the cores are drawn into the solenoid coils after each set of wheels clears the teeth.
In the type of barrier having individually pivoted teeth, there is no known means for simultaneously lowering all teeth below the road surface when it is desired to permit traffic to flow in both directions. In this regard, each wheel passing in the allowed direction will depress only those two or three teeth spanned by the wheel, and such teeth snap back to normal projecting positions via their springs after the wheel clears them. Further, such a mechanism is undesirably time consuming and expensive to assemble, maintain and repair. For example, should a tooth be broken by the wheel of a vehicle that attempted to pass over the barrier in the wrong direction, it is necessary to remove the surface plate, disconnect the springs where they are connected to the embedded housing, lift the shaft with the hubs and shaft support plates from the housing, and slide the hubs off the shaft until the one with the broken tooth is removed. Thereafter, a hub with an unbroken tooth is replaced for the one removed, and the remaining hubs are replaced on the shaft along with the shaft support plates, following which such subassembly is lowered into the housing and the ends of the springs are connected against the anchor tabs in the housing together with the spring that is connected to the replacement tooth hub.